Grand piano action



Sept. l5, 1931. c. N. HlcKMAN 1,823,142

GRAND PIANO ACTION Original Filed July 25. 1928 3 Sheets-Sheet l I umSept. 155.1931. c. N. HICKMAN 1,823,1424.

GRAND PIANO ACTION original Filed July 25. 192s 5 sheets-sheet 2 wwwHIIIIIIHIUl-IIl-l lili "v lnlllllmmh mmm Sept. l5, 1931. c. N. HlcKMANGRAND PIANO ACTION Original Filed July 25. 1928 3 Sheets-Sheet 5Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE CLARENCE N.HIC'KMAN, OF JACKSON HEIGHTS, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS,TO AMERICAN PIANO CORPORATION, OF EAST ROCHESTER, NEW

YORK, A CORPORATION OF DELAWARE GRAND PIANO ACTION Application ld July25, 1928, Serial No. 295,258. Renewed March 19. 1930.

This invention relates to hammer actions for stringed musicalinstruments.

lt is an object of the present invention to provide an action whichshall be simple in construction, which shall fullill` all of the usuairequirements of such actions with respect to freedom of rebound,rapidity of repetition and so forth, but which shall also have inherentoperating advantages of value w which are not provided by the usuallhammer actions. For example, it is an object of the invention to providean action having greater smoothness and ease of operation, an actionwhich will provide improved tone quality, an laction which will permitbi-gger fortissimos to be obtained. and an action which will provideimproved control for pianissimo playing. lt is also an object of theinvention to provide greater ease and permanence of adjustment than isusual in ordinary piano actions.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes ofillustration is shown in the accompanying drawings, in which,

Figure l is a section through an action, showing one unit thereof inelevation, the parts being shown in normal rest position.

Figure 2 is a similar view showing the position of the parts as thehammer approaches the string, and in broken lines, showing the hammer incontact with the string.

Figure 3 is a similar view showing the position of the parts after therebound of the hammer, but before release of the key.

Figures 4, 5 and 6 are enlarged detail sectional views of the piujoints, and

Figure 7 is a section on the line 7 7 of Figure 1.

tiefer-ring to the drawings, the individual units of the action are eachmounted, in the usual manner, upon the hammer flange rail l which issupported at intervals along its length by the brackets 2, the hammeriange 3 of each unit being secured to said rail by means of screws 4.Pivotally mounted on the iange 3 by means of pin joint 5 is asubstantially L-shaped member 6 which may be called the driver, andpivotally mounted on said driver by means of pin joint 7 is the hammershank 8 carrying hammer 9.

Also pivotally connected to the driver 6 by means of pin joint 10 is amember 11 which may be referred to as the upper knuckle link, andpivotally connected to said upper knuckle link by means of pin joint 12is a lower knuckle link 13. For convenience, the pin joint 12 may bereferred to as the knuckle joint.

T he lower knuckle link 13 is operatively connected with the key 14 bymeans of pin joint 15, Hange 16, spring clip 17, and capstan screw 18,the capstan permitting easy adjustment between the key and knucklelinks, and the clip 17 providing a convenient connection which may bereadily attached or detached when desired.

Secured to the brackets 2 are brackets 2() carrying a transverse member21 which may be called the driver stop. Preferably this member ischannel shaped to receive a strip of silencing material 22 such as feltor bushing cloth and is so located as to be in the operative path of thedriver stop screw 23 carried by the depending arm of the driver G, whichis adjustable to limit the travel of the driver 6 to any desired extent.Prefer ably the said screw is so adjusted as to permit the driver tocarry the hammer to a position closely adjacent the string (asillustrated in Figure 2) as for example, within g of the string, andpreferably even closer, but may be otherwise adjusted if desired.

ln the normal position of rest illustrated in Figure 1, the knucklejoint 12 is urged, under the influence of repetition spring 24, to aposition such that it is slightly in front of the line of centersconnecting the joints 10 and 15, but is prevented from moving further inthis direction b v the knuckle stop 25, comprising abutting faces havinga strip of silencing material therebetween.

The point of connection of the spring 24 to the knuckle member 13 may belocated in such position as to provide any desired rapidity of return ofthe knuckle links to norlil:

mal position after the joint is broken as hereinafter described.

Secured to the front face of knuckle link 11 is a strip ot' silencing;Fmaterial 26, mounted in position to lie in the operative path of knucklebreaker 27 carried by the driverl 6. The knuckle breaker is preferablyan adjustable screw and is adjusted in such manner that as the driverswings on its pivot 5 the knuckle breaker will move into contact withthe pad 26 shortly before driver stop screw 23 comes into contact withdriver stop 22, the result beingA that the knuckle joint is pushed tothe rear of the line ot centers coniieeting joints 10 and 15 for reasonswhich will be apparent hereinafter.

In order to provide an action ot great durability, the pin joints havebeen carefully constructed. Joints 7 and 12 are similar and areillustrated in Figure 4. ln these joints the pin 30 is fixed in thecentral meniber, and the ends rotate in the bushings 31, preferably ol"bushing cloth. The joint 5 is illustrated in Figure 5 and is similarlyconstrurted, except that the bushings are preferably ot relatively hardmaterial, such as a phenol condensation product impregnated withgraphite. In joints 10 and 15. on the other hand, the pin 33 is liXed inthe outer members and rotates in a bushingr 34, preferably of bushingcloth, in the central menibers. washers 35 of bushing cloth beingprovided to permit a certain amount ot lateral freedom.

The so-called repetition sprinnj serves to balance the weight of thehammer 9 and the driver 6, and in order that the effectiveness of thespring may be varied in different sections of the piano in which theweight of these parts may differ` means are provided. in the preferredembodiment illurtrated.y tor shitting;r the point of attachment ot oneend of the spring. Thus a plurality of spaced holes 36 are provided inthe driver 6. In the position illustrated the fpring is least effective,but as it is proiyzessively moved to other pos ions. its ellective'icssis increased.

This spring is preferably so adjusted 'that when the parts are in theposition illust rated in Figure 3. it the key i; released somewhat so asto free the hammer from the back check 39, the han'imer will moveslightly upwardly toward the string.

As will be observed. when the entireA artioii is adjusted in thismanner, although the effectiveness oi the ing is different in differentsections of the action. the pressure ot the sprintf on the keys isuniform throughout the action.

In order to prf-,vent a rei-tain action known as freezing which maysometimes occur in rase ot' extraordinarily rapid repetition. or in caseof an extremely heavy blow this ter i heinev used in cases in which therear end of the key may return only part of the way to its normalposition and may start upward again before the knuckle joint returns tonormal position, or in cases in which tlu,` hammer on rebound drivesitself deeply into the backcheck the shoulder 4U is provided on thedriver 6 to cooperate with the shoulder 41 on the member 11, a pad 42 offelt or other silencing material being located therebetween.

As will be observed, under the extraordinary conditions described, theshoulders may engage either to cause the knuckle members 11 and 13 toassume normal position. or else said shoulders may engage to prevent thehammer from being driven back sufliciently to cause the backcheck tolock the hammer on the neXt succeeding stroke of the key.

As previously explained, the normal rest position ot the action isillustrated in Figure 11 t' now.y the forward end of' the key (notillustr ted) is depressed, the rear end of the key 14 rises toward thekey stop rail 37, and the upward motion of the key is transmittedthrough the capstan screw 18 and parts 17 and 16 to the knuckle links 13and 11. Since at this time the pin joint 12 is in liront of the line otcenters connecting; the pin joints 1() and 15, the upward thrust of thekey is transmitted directly through the knuckle links to the driver 6,causing the driver to swingy about the pin joint 5 so as to carry thehammer 9 in the direction of the string 38. As the driver 6 swings aboutthe pivot 5, the knuckle breaker screw 27 eventually comes into Contactwith the pad 26, thus causingr the pin joint 12 to be pushed rearwardlyot the line of centers connecting the pin joints 1() and 15. Almostimmediately therezfifter. the driver stop screw 23 comes into contactwith the driver stop 22, thus preventing any further swinging motion ofthe driver 6 in that direction. The acquired momentum ot' the hammer 9.however. causes it to swinir about the pin joint 7 to impart a blow tothe string!y 38. after which the hammer rebounds freely from the stringYagainst the silencing material 29 which is secured to the driver 6. Thedowward momentum of the hammer acquired on the rebound is nowtransmitted to the driver 6. causing the said driver to swing; in aclockwise direction. but inasmuch as the pin joint 12 is now to the rearof the line of centers connecting the pin joints 10 and 15 asillustrated in Figure 2, such clockwise motion of the driver 6 onlyresults in a further breaking of the knuckle joint as illustrated inFigure 3. and this continues until the rebound ot the hammer is stoppedbv engagement of the hammer with the backcheek 39. If now the key isreleased entirely by the operator, the backelieek 35) rst swings awayfrom the hammer. permitting the repetition spring 24 to raise the driverand hammer slightly. This in turn permits the spring 24 to thrust theknuckle link pivotally connected to said knuckle members 11 and 13 tonormal position, alter Which the Weight of' the key serves to pull theknuckle links and connected parts to their original positions asillustrated in Figure I. Preferably the rear ends of the keys areweighted for this purpose.

ln some cases, as with very rapid repetition the key is only permittedto return part way toward normal rest position before another blow isimparted. Under such circumstances the knuckle links return to positionsuch that the knuckle joint is in iront of the line of centersconnecting joins l0 and 15 as soon asthe humilier is even slightlyreleased, and with sufficient rapidity so that the next impulse may betransmitted through the knuckle links in the usual manner.

It will be understood that the invention may be variously modified andembodied within the scope of the subjoined claims.

I claim as my invention:

1. In a grand piano action adapted to be operated by a key, incombination, a driver pivotally mounted upo-n a ixed member of thepiano, a hammer pivotally mounted on said driver, a knuckle linkpivotally connected to said driver, a second knuckle link pivotallyconnected to said first knuckle link and pivotally connected to saidkey, cooperating shoulders on said knuckle links to limit pivotalmovement of said links with respect to each other in one direction,whereby a thrust transmitting connection is provided between said keyand said driver, a depending arm forming part of said driver andarranged to contact with said knuckle links to break said thrusttransmitting connecton during the latter portion of hammer actuatingmovement thereof, means i'or limiting the motion of said driver towardsaid string, and a compression spring connected to said driver and tosaid second knuckle link.

2. In a grand piano action adapted to be operated by a key incombination, a driver pivotally mounted pon a lixciil meinber ot' thepiano, a hammer pivotally mounted on said driver, a knuckle linkpivotally connected to said driver, a second iir knuckle link andpivotally connected to said key, cooperating shoulders on said kn kielinks to limit pivotal movement ot said l with respect to each other inone direction. whereby a thrust transmitting connection is providedbetween said key and said driver, a depending arm forming part of saiddriver and arranged to contact with said knuckle links to break saidthrust transmitting connec-tion during the latter portion of hammeractuating movement thereof.

3. In a piano action adapted to be operated by a key, in combination, adriver pivotally mounted upon a fixed member ot the piano, a hammerpivotally mounted on said driver, a pair of knuckle links, pivotallyconnected to each other and pivotally connected to the driver and key,respectively, and providing a thrust transmitting connectiontherebetween, and means whereby motion of said driver may move saidknuckle links to break said thrust transmitting connection prior toimpact ot the hammer against the string.

4. In a piano action, adapted to be operated by a key, in combination, adriver pivotally mounted upon a fixed member of the piano, a hammerpivotally mounted on said driver, a pair of knuckle links, pivotallyconnected to each other and pivotally connected to the driver and key,respectively, and providingr a thrust transmitting connectiontherebetween, means whereby motion of said driver' may move said knucklelinks to break said thrust transmitting connection prior to impact otthe hammer against the string. and means for limiting the motion ot saiddriver toward said string.

5. In apiano action adapted to be operated by a key, in combination, adriver pivotally mounted upon a fixed member of the piano.. a hammerpivotally mounted on said driver, a 1air o knuckle links, pivotaliyconnected to eich other and pivotaliy connected to the driver and key,respectively, and providing a thrust transmitting connectiontherchctwecn, means whereby motion of said driver may move said knucklelinks to break said th rustl transmitting connection prior to impact ofthe hammer against the string, and a compression spring` connected tosaid driver and to said knuckle links.

6. In a piano action adapted to be operated by a key, in combination, ahammer mounted to swing against a string, a thrust transmittingconnection intermediate said key and said hammer, and means actuated bysaid key for breaking said thrust tra-nsinitting connection prior toimpact of the hammer against he string.

7. In a piano action adapted to be operated by a key, in combination, ahannner mounted to swing from position ot rest to a position tor impactagainst a string, means, providing a thrust transmitting connectionbetween said key and said hammer, and means pivolally mounted on a fixedpart ot' the piano and actuated by said key for breaking said thrusttransmitting connection prior to impact of the hammer against thestring.

8, In a grand piano action adapted to be operated by a ker. incombination, a driver movably mounted upon a tixcd member ot the piano.a hammer inovabfy mounted on said driver` and th rt tr; mitting connctions betr-:ecn said. driver and key.

S). In a grand piano action adapted to be operated by a key, incombination, a driver movably mounted upon a iXed member of the piano, ahammer movably mounted on said driver, thrust transmitting connectionsbetween d driver and key, and means for break' ig :aid conl'tectionsprior to impact of the hammer against the string.

10. In a grand piano action adapted to be operated by a key, incombination, a driver movably mounted upon a iiXed member ot the piano,a hammer movahiy mounted on said driver, and means for limiting themovement ot said drive' in the direction of the string.

ll. In a grand piano action adapted to be operated by a i'ey. incombination, a driver movably monnted upon a fixed member ot the piano.a hammer movably mounted on said driver, thrust transmitting connectionsbetween said driver and key, and means tor limiting' the movement otsaid driver in thc direction of the string.

l2. In a piano action adapted to be operated by a key, in combination. adriver movably mounted upon a iixed member of the piano, a hammermovably mounted on said driver, and a compression spring having one endbearing against said driver and the other end bearingagainst said key,said spring being adjusted to balance the weight of the driver andhammer.

13. In a piano action adapted to be operated by a key, in combination, adriver movably mounted upon a tiXed member ot the piano, a hammermovably mounted on said driver, and means to balance the weight ot thedri ser and hannner.

14. In a piano action :ulapted to be operated by a key, iii fombination,a driver movably mounted upon a iiXed member ot the piano, a hammermovabiy mounted on said driver, and a compression spring having one endbearing against said driver and the other end heaving` against said key,and means whereby the position ot the driver end ot the spring may bevaried depending upon the weight ci the parts of the action.

'15. In a piano action adapted to be operated by a key in combif ion, ahammer mounted to swing from a position ot rest to a position tor im'1act against a string, means proviizing a, thrusi transmitting connectionbetween said key and said han'nner, and means actuated by said key tomove into contact with said thrust tr ismitting connection to break saidconnection prior to impact ot the hamme against the string.

1G. In a grand piano action adapted to be operated by a k y. incombination, a hammer mounted to swing from a position of rest to aposition for impart against a string, connectitms` between the key andhammer for actuating the hannner and means for positively limiting themovement of said actuating connections in hammer actuating direction.

17. In a grand piano action adapted to be operated by a key, incombination, a hammer mounted to swing from a` position ol rest to aposition for impact against a string, a driver having connection withsaid hammer and key, and means for positively limiting the movement ofsaid driver in hammer actuating direction.

I8. In a grand piano action, adapted to be operated by a key, incombination, a driver movabiy mounted upon a fixed member ot the piano,a hammer movably mounted on said driver', a pair of knuckle links,pivotally connected to each other and pivotally connected to the driverand key, respectively, and providing a thrust transmitting connectiontherebetween, means whereby motion ot said driver may move said knucklelinks to break said thrust transmitting connection prior to impact ofthe hammer against the string, and resilient means for returning saidknuckle links to normal position.

19. In a piano action adapted to be operated by a` key, in combination,a hammer mounted to swing from a position of rest to a position forimpact against a string, means providing a thrust transmittingconnection between said key and said hammer, said connection including aclip detachably secured to the key.

Q0. In a piano action adapted to be operated by a key, in combination, ahammer mounted to swing from a position of rest to a position for impactagainst a string, means providing a thrust transmitting connectionbetween said key and said hammer, said connection including a capstanscrew and a clip detachably secured to the head ot said capstan screw.

21. In a piano action, in combination, a driver movably mounted upon afixed member of the piano and means for positively lin'iiting themovement ot said driver in hammer actuating direction, said meansincluding a channel member mounted upon a fixed member of the piano anda strip of silencing material mounted in said channel member.

In a` grand piano action adapted to be perated by a key, in combination,a driver pivotally mounted upon a iiXed member of the piano, a hammerpivotally mounted on said driver, a knuckle link pivotaily connected tosaid driver, a sec nd knckle link pivotally connected to said first.knuckle link and pivotaliy connected to said key, cooperating shoulderson said knuckle links to limit pivotal movement ot said links withrespect to each other in one direction, whereby a thrust transmittingconnection is provided between said key and said driver, a depending armforming part oi said driver, and an adjustable screw mounted in saiddepending arm and arranged to contact with said knuckle links to breaksaid thrust transmitting connection during the latter portion of hammeractuating movement thereof.

23. In a grand piano action, adapted to be operated by a key, incombination, a drivel' pivotally mounted upon a fixed member ot thepiano, a hammer pivotally mounted on said driver, a pair of knucklelinks, pivotally connected to each other and pivotady connected to thedriver and key, respectively, and providingl a thrust transmittingconnection therebetween, means whereby motion of said driver may movesaid knuckle links to break said thrust transmitting connection prior toimpact of the hammer against the string and means for limiting themotion of said driver toward said string, said means including anadjustable screw carried by said driver.

24. In a piano action adapted to be operated by a key, in combination, adriver movably mounted upon a fixed member of the `piano, a hammermovably mounted on said driver, and means for limiting the movement ofsaid driver in the direction of the string, said means includingr anadjustable screw carried by said driver.

In a piano action adapted to be operated by a key, in combination, adriver movably mounted upon a fixed member ot the piano, a hammermovably mounted on said driver, thrust transmitting connections betweensaid driver and key, means for breaking said connections prior to impactof the hammer against the string, and resilient means for returning saidthrust transmitting connections to normal position.

2G. ln a piano action adapted to be operated by a key, in combination, adriver movably mounted upon a fixed member of the piano, a hammermovably mounted on said driver, thrust transmitting connections betweensaid driver and key, and means for breaking said connections prior toimpact of the hammer against the string, said means including anadjustable screw carried by said driver.

27. ln a piano action adapted to be operated by a key, in combination, adriver movably mounted upon a fixed member oiE the piano, a hammermovably mounted on said driver, a pair of knuckle links pivotallyconnected to each other and pivotally connected to said driver and key,respectively, and providing a thrust transmitting connectiontherebetween, and means including cooperating abutting faces on saiddriver and one ot said knuckle links for preventing freeziiw.

In a piano action adapted to be operated by a key, in combination, ahammer, driving connections between said key and hammer, a backeheck,and means to retard the rebound of the hammer and restore the drivingconnections to original positions.

29. In a piano action adapted to bc operated by a key, in combination, ahammer, driving connections between said key and hammer, including aknuckle link, a backcheck, and means for transmitting the rebound thrustoi said hammer to said knuckle links subsequent to engagement of saidhammer by said backcheck.

30. In a piano action adapted to be operated by a key, in combination, ahammer, driving connections between said key and hammer, a backeheclv,and means` for transmitting the rebound thrust of said hammer to saiddriving connections subsequent to engagement of said hammer by saidbackcheck.

31. A piano action comprising in combination, a key, a hammer, drivingmeans between said key and hammer, and means set into motion by said keyfor arresting the action of said driving means upon said hammer.

32. A piano action comprising in combination, a key, a hammer, drivingmeans between said key and hammer, and means set into motion by said keyand having an amplitude of movement greater than that ot the key forarresting the action of said driving means upon said hammer.

A piano action comprising in combination, a key, a hammer, knuckle linksfor projecting said hammer by movement of said key, and moving means forbreaking the joint of said knuckle links.

34. A piano action comprising in combination, a key, a hammer, knuckielinl s for projecting said hammer by movement of said key, and meansmovable transversely of said links Tfor breaking the joint therebetween.

A piano action comprising in combination, a key, a hammer, knuckie linksfor projecting said hammer by movement of said key, and means includingan L-shaped member for breaking the joint of said knuckle links whenmoving in one direction and for restoring said links to operativecondition in another direction.

36. A piano action comprising in combination, a key, a hammer, a directbreakable driving connection between said key and hammer, and :i springconnected across the breakable joint of said driving connection.

37. A piano action comprising in combination, a key, a hammer, a directbreakable driving connection between said key and hammer, and meansmoving bodily with said driving connection and actingI to support saidhammer when the driving action of said connection has been discontinued.

A piano action comprising in combination, a key, a hammer, a directbreakable driving connection between said key and hammer, and a freefloating resilient connection acting upon said hammer upon its reboundstroke almost immediately after it leaves the piano string.

39. In a piano action in combination, a key, a hammer, driving linksbetween said key and hammer and an intermediate member pivotallyconnected to said hammer and links and provided with abutment surfacesadapted to cooperate with said hammer and links respectively.

40. In a piano action in combination, a key, a hammer, driving linksbetween said key and hammer and an intermediate member pivotallyconnected to said hammer and links and provided with a free end disposedbetween said hammer and links and having abutment surfaces for each.

41. In a piano action, in combination, a key, a hammer, drivingconnections between said key and hammer including a driver movablymounted on a fixed member of the piano, and thrust transmittingconnections between said driver and key, said hammer being mounted toswing on said member, and said thrust transmitting connections beingconnected to said driver at a point between its connection to saidi'iXed member and its connection to said hammer.

In testimony whereof, I have signed my name to this specification this20th day of July, 1928.

CLARENCE N. HICKMAN.

